package Network;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.nio.charset.StandardCharsets;

public class UDPEchoServer {
    private DatagramSocket socket = null;
    public UDPEchoServer (int port) throws SocketException {
        socket = new DatagramSocket(port);
    }
    public String process(String request) {
        return request;
    }
    public void start() throws IOException {
        System.out.println("服务器启动");
        while (true) {
            DatagramPacket requestPacket = new DatagramPacket(new byte[4096], 4096);
            socket.receive(requestPacket);
            String request = new String(requestPacket.getData(), 0, requestPacket.getLength());
            String response = process(request);
            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(), response.getBytes().length,
                    requestPacket.getSocketAddress());
            socket.send(requestPacket);
            System.out.printf("[%s,%d],rep: %s,resp: %s\n", requestPacket.getAddress().toString(), requestPacket.getPort(), request, response);


        }
    }


    public static void main(String[] args) throws IOException {
        UDPEchoServer udpEchoServer = new UDPEchoServer(9090);
        udpEchoServer.start();
    }
}
